An increasing number of manufacturers provide conversion kits for changing a particular caliber of weapon, particularly handguns, from one caliber to another. For example conversion kits are known for converting weapons that normally fire 9 mm ammunition to a weapon that will fire, for example, 22 caliber cartridges. Such a practice allows a user to practice with a weapon of choice while using much less expensive ammunition. Generally, the conversion kit includes at least a new barrel and slide and a magazine for carrying the new ammunition. In the past, such magazines have been created from a sheet steel material that is bent into a box-shape or from a molded plastic material. Both of these approaches entail difficulties in manufacturing, particularly in maintaining tolerances.